Microwave caramels and cream in microwaveable bowl on MEDIUM 4 minutes or until caramels begin to melt. Stir until caramels are completely melted. Spread evenly over chocolate layer; sprinkle with walnuts. Cool on pan on wire rack. Remove dessert from pan, using foil handles. Cut into 18 bars, then cut each bar diagonally in half to form 2 triangles.